CN104815748B - The broken mill floatation process of two sections of coal in a kind of coking - Google Patents

Abstract

The invention discloses a two-stage crushing, grinding and flotation process for medium coal in coking. Mine dissociation operations, slime water concentration and clarification operations, and filter press operations. The equipment includes rolling screen crusher, single-stage slurry mixing tank, multi-stage slurry mixing tank, flotation machine, tailing coal buffer tank, grading feeding pump, grading cyclone, spiral separator, vibrating arc Sieve, ball mill, grinding coal slime buffer tank, grinding coal slime feeding pump, thickener, thickening underflow pump, filter press buffer tank, filter press feed pump, quick opening filter press. The beneficial effect of the present invention is to realize the dissociation of interbedded coal with fine particle size; the two dissociations reduce energy loss, and also effectively reduce fine mud pollution of clean coal caused by non-selective grinding of high-ash particles severity.

Description

A two-stage crushing, grinding and flotation process for medium coal in coking

technical field

The invention belongs to the technical field of coking medium coal separation and relates to a two-stage crushing and flotation process for coking medium coal.

Background technique

The continuous improvement of coal production ensures the steady development of my country's national economy, and the demand for coking coal to support the iron and steel industry is growing day by day. Although my country is rich in coal resources, the reserves of coking coal are relatively small, and the reserves of high-quality coking coal (such as main coking coal and fat coal) are even rarer. In addition, this part of the rare resource raw coal has high ash content and high content of medium coal. After separation, the yields of clean coal, medium coal and gangue each account for about 1/3, which further reduces the output of scarce coking coal and clean coal. If the low-ash clean coal in this part of medium coal can be recovered, it will not only achieve greater social and economic benefits, but also play a positive role in ensuring my country's energy security.

Effective dissociation of middling coal is the premise of separation, and for intercalated coal resources with fine or very fine particle size, even if it is broken to less than 6 mm or 3 mm, it cannot be dissociated to obtain more coarse-grained and low-ash clean coal. On the one hand, due to the fine particle size of the embedded distribution, coal and gangue still exist in the form of conjoined bodies under larger dissociated particle sizes; on the other hand, due to the difference in properties between gangue and coal, most of the dissociated low-ash particles exist in fine Among the grains, the coarse grains are mainly the medium coal intergrowth with finer grain size and high-ash gangue, which means that a large amount of low-ash clean coal cannot be obtained by gravity separation after crushing. For coking medium coal with fine particle size and hard gangue, most of the dissociated fine particles are mainly recovered by flotation. Due to the unavoidable generation of high-ash fine mud during the dissociation process of medium coal, and the existence of some incompletely dissociated medium coal intergrowths, the pollution of fine sludge during the flotation process results in high ash content of clean coal and incomplete dissociation of medium coal intergrowths However, the problem of low ash content in tailing coal is difficult to be effectively solved. Therefore, in view of the coexistence of serious pollution of clean coal and low ash content of tailing coal in coking coal flotation, it is of great significance to propose a process that can realize effective dissociation and high-efficiency separation of middling coal for the secondary recovery and utilization of scarce coal resources.

Contents of the invention

The purpose of the present invention is to provide a two-stage crushing, grinding and flotation process for medium coal in coking, which solves the problem of the unavoidable generation of high-ash fine mud during the dissociation process of medium coal, and the existence of some incompletely dissociated medium coal conjoined bodies. The fine mud pollution in the flotation process leads to high ash content in clean coal, incomplete dissociation of medium coal and low ash content in tailing coal.

The technical scheme adopted in the present invention is to carry out according to the following steps:

a. Crushing operation: feed the coking medium coal into the rolling screen crusher to obtain a crushed product;

b. Blending operation: in blending equipment 1: a section of crushed product is given to the single-stage impeller blending mixing tank for sufficient blending, and the blending time is not less than 4 minutes;

In the slurry mixing equipment 2: the second-stage grinding fine coal slime is fed into the multi-stage forced stirring slurry mixing equipment, the linear speed of the stirring impeller is not less than 6m/s, and appropriate circulating water is added according to the concentration requirements during slurry mixing;

c. Flotation operation: the crushed product of the first stage and the fine coal slime of the second stage grinding are sent to the flotation equipment for separation after slurry adjustment, and the flotation clean coal and tailing coal are obtained;

d. Grading and dehydration operation: the tailing coal enters the tailing coal pond for buffering and then pumps it to the classifying cyclone for classification;

e. Coarse slime tailing operation: the underflow of the classifying cyclone is fed to the spiral separator for tailing, and the heavy and light products of the spiral separation are obtained;

The overflow of the graded cyclone and the heavy product enter the concentrator and then concentrate and press filter;

f. Curved sieve desliming operation: Light products enter the curved sieve for desliming and dehydration to obtain the oversize and undersize;

g. Grinding and dissociation operation: the oversieve is fed into the coal mill for grinding and dissociation. The mill speed can be adjusted according to the nature of the feed material and the dissociation particle size. The part with a dissociation particle size of 0.074mm accounts for 50-60%. The separated ore pulp is pumped to the pulping equipment 2 for pulping;

h. Concentration and clarification of coal slime water: the overflow of the grading cyclone, the heavy product of the spiral separator and the sieve of the curved sieve are fed into the concentrator for concentration and clarification to obtain an underflow slurry with a suitable concentration for subsequent pressure filtration, and the overflow is used as Recycled water;

I. Press filter operation: after buffering, the underflow slurry of the concentrator is pumped to the diaphragm quick-opening filter press for press filtration. The filter cake is used as the final tailing slime product, and the filtrate is used as circulating water.

Further, in the step a, it is crushed to less than 1mm.

A two-stage crushing, grinding and flotation equipment for medium coal in coking, including a rolling screen crusher, a single-stage slurry mixing tank, a multi-stage slurry mixing tank, a flotation machine, a tailing coal buffer tank, a graded feed pump, and a graded feed pump. Cyclones, spiral separators, vibrating arc screens, ball mills, grinding coal slime buffer tanks, grinding coal slime feeding pumps, thickeners, concentrated underflow pumps, filter press buffer barrels, filter press feed pumps, fast open filter press;

Among them, the rolling type sieving crusher is connected to a single-stage slurry mixing tank, and the single-stage slurry mixing tank is connected to a multi-stage slurry mixing tank and a flotation machine respectively, and a multi-stage slurry mixing tank is connected to a grinding coal slurry feeding pump. The coal slime feed pump is connected to the grinding coal slime buffer pool, the grinding coal slime buffer pool is connected to the ball mill, the ball mill is connected to the vibrating curved screen, the vibrating curved screen is connected to the thickener and the spiral separator respectively, and the spiral separator is connected to the The thickener and the graded cyclone, the graded cyclone are respectively connected to the thickener and the graded feeding pump, the graded feeding pump is connected to the tailing coal buffer tank, the tailing coal buffer tank is connected to the flotation machine, the thickener is connected to the concentrated underflow pump, and the concentrated underflow The pump is connected to the filter press buffer barrel, the filter press buffer barrel is connected to the filter press feed pump, and the filter press feed pump is connected to the quick-open filter press.

The beneficial effect of the present invention is to realize the dissociation of interbedded coal with fine particle size; the two dissociations reduce energy loss, and also effectively reduce fine mud pollution of clean coal caused by non-selective grinding of high-ash particles severity.

Description of drawings

Fig. 1 is a schematic diagram of the present invention's coking medium coal two-stage crushing and flotation process;

Fig. 2 is a schematic diagram of the structure of the coking medium coal two-stage crushing and flotation equipment of the present invention.

detailed description

The present invention will be described in detail below in combination with specific embodiments.

The present invention aims to provide a high-efficiency separation process for coking medium coal, which crushes the coking medium coal (with a particle size of about 50 mm) to a smaller particle size (below 1 mm) and recovers the dissociated fine-grained clean coal by flotation, throwing Coarse tailing coal particles are further ground and dissociated to recover low-ash particles with extremely fine particle size. At the same time, according to the difference in particle size between the two, the two are recovered together through independent slurry mixing-mixed flotation enhanced slurry mixing process . The combination of the two-stage crushing and pulping process solves the problem of low ash content in the tailing coal caused by serious pollution of clean coal fine sludge and incomplete dissociation, and provides a coking medium with low operating cost, high separation efficiency and remarkable economic efficiency. coal sorting method. Technical solution: The present invention is a two-stage crushing-flotation process for coking medium coal, which mainly includes the following steps: a. Crushing operation: feeding the coking medium coal into a rolling-type screening crusher, the equipment has crushing and sieving,

Crush the material to less than 1mm to obtain a first-stage crushed product, and the crushed material is fed into the single-stage pulping and stirring

Mixing equipment for mixing.

The heavily selected coal (50mm) is fed into the rolling-type screening crusher, which has the function of crushing and screening. Through the forced rolling action, the crushing and dissociation of the embedded finer coal slime is realized, and the selective crushing effect is strengthened, so that Coal is dissociated and enriched into fine-grained grades, which is beneficial to the separation and recovery of subsequent flotation.

b. Slurry mixing operation:

In pulping equipment 1: send a section of crushed product to the single-stage impeller slurrying mixing tank, fully ensure the slurrying time (not less than 4 minutes), so as to ensure that the collector and coal particles are fully adsorbed; in slurrying equipment 2: The second-stage grinding fine coal slurry is fed into the multi-stage forced stirring slurry mixing equipment (the linear speed of the stirring impeller is not less than 6m/s), so that the dissociated fine particles and collectors are fully dispersed and effectively adsorbed in the slurry mixing equipment. The recovery rate and selectivity of the separation are enhanced by adjusting the pulping time and the pulping speed of the floating coal slime. Add appropriate circulating water according to the concentration requirements during pulping to ensure that the flotation concentration is around 60-80g/L. The crushed material and the fine-grained flotation tailings coarse-grained medium coal are ground and the materials are slurried separately before flotation to realize the recovery of the finer-grained clean coal and the extremely fine-grained low-ash particles , which not only simplifies the process, reduces the energy consumption of crushing, but also reduces the pollution of flotation clean coal fine slime by reducing the amount of high-ash fine mud and strengthening the pulping process. Incompletely lead to the problem of low ash content in tailing coal.

c. Flotation operation: the crushed product of the first stage and the fine coal slime of the second stage grinding are sent to the flotation equipment for separation after slurry adjustment, and the flotation clean coal and tailing coal are obtained. This operation is adjusted according to the actual ash content requirements. When the ash content of the clean coal exceeds the standard, it can be roughly selected to ensure that the ash content of the clean coal is qualified. The flotation tailings are then sent to a classifying cyclone for classification (classification particle size is 0.074mm or 0.125mm).

d. Grading and dehydration operation: the tailing coal enters the tailing coal pond for buffering and then pumps it to the classifying cyclone for classification;

e. Coarse slime tailing operation: the underflow of the classifying cyclone (coarse flotation coal tailings) is fed to the spiral separator for tailing, and the heavy and light products of the spiral separation are obtained; the overflow of the classifying cyclone After entering the concentrator with the heavy product, it is concentrated and filtered to improve the working effect of sedimentation and pressure filtration;

f. Arc sieve desliming operation: light products enter the arc sieve for desliming and dehydration to obtain oversize and undersize; g. Grinding and dissociation operations: oversize is fed into the coal mill for grinding and dissociation, The speed of the mill can be adjusted according to the nature of the feed material and the dissociated particle size. The part with a dissociated particle size of 0.074mm should account for 50-60%.

h. Coal slime water concentration and clarification operation: the overflow of the classifying cyclone, the heavy product of the spiral separator and the undersize of the curved screen are fed into the thickener for concentration and clarification to obtain an underflow slurry with a suitable concentration (400-600g/L) Subsequent pressure filtration, the overflow is used as circulating water;

I. Press filter operation: after buffering, the underflow slurry of the concentrator is pumped to the diaphragm quick-opening filter press for press filtration. The filter cake is used as the final tailing slime product, and the filtrate is used as circulating water.

Beneficial effects: the invention is a sorting process of crushing-grinding and dissociation of medium coal, through two stages of crushing and dissociation combined with flotation to realize dissociation and separation of coking medium coal with fine particle size. The 50mm coking medium coal is crushed to less than 1mm at one time by using a rolling sieving crusher to realize the dissociation of the interbedded coal with a finer particle size; The dissociation of medium coal with extremely fine particle size; the two dissociations reduce energy loss, and also effectively reduce the severity of fine mud pollution of clean coal caused by non-selective grinding of high-ash particles. In addition, the pulping process before the two-stage dissociated material flotation is strengthened, and the recovery rate of coarse grains and the selectivity of fine grains are ensured by matching the pulping time and pulping intensity respectively, and the two-stage crushing-flotation process is applied for the first time to realize coking Efficient separation of medium coal.

Advantage of the present invention also has:

A. Feed the re-selected coal (50mm) into the roller-type screening crusher, and realize the crushing and dissociation of the finer-sized coal slime through forced rolling, and strengthen the selective crushing effect, so that the coal is dissociated and enriched To the fine particle level, it is beneficial to the separation and recovery of the subsequent flotation.

B. The crushed material is directly flotation, and the coarse-grained gangue with high hardness and the medium-sized coal conjoined body with extremely fine particle size are discharged from the flotation tailings, and the flotation tailings are coarse-grained and thrown, and then recycled Embedded low-ash clean coal with extremely fine particle size; two-stage crushing-flotation and segmental dissociation pulping simplifies the process, reduces the energy consumption of crushing, and at the same time reduces the impact of ineffective crushing and grinding on high-ash coarse particles The fine mud pollution caused by subsequent flotation has solved the problem of low ash content in the tailing coal caused by the continuous generation of medium coal.

C. According to the different requirements of the crushed material and the second-stage grinding coal slurry on the energy input of pulping, different mixing and pulping equipment are matched. The first-stage crushed material is fed into the single-stage impeller mixing tank to fully ensure the mixing time (the mixing time is not less than 4 minutes) so that the flotation collector can be fully adsorbed on the particle surface to improve the recovery rate of coarse particles; the second-stage grinding coal The mud is fed into the multi-stage forced stirring slurry mixing equipment to ensure high stirring speed (the linear speed of the stirring impeller is not less than 6m/s) to fully disperse and effectively adsorb fine-grained coal slime and collectors.

D. The process is simple and feasible, with less investment, low power consumption, low operating costs, high sorting efficiency and remarkable economic benefits.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Any simple modifications made to the above embodiments according to the technical essence of the present invention, equivalent changes and modifications, all belong to this invention. within the scope of the technical solution of the invention.

Claims (2)

1. A two-stage crushing and flotation process for medium coal in coking, carried out according to the following steps: a. Crushing operation: feed the coking medium coal into the rolling screen crusher to obtain a crushed product; b. Blending operation: In blending equipment Ⅰ: a section of crushed product is given to the single-stage impeller blending mixing tank for sufficient blending, and the blending time is not less than 4 minutes; In the slurry mixing equipment II: the second-stage grinding fine coal slime is fed into the multi-stage forced stirring slurry mixing equipment, the linear speed of the stirring impeller is not less than 6m/s, and appropriate circulating water is added according to the concentration requirements during slurry mixing; c. Flotation operation: the crushed product of the first stage and the fine coal slime of the second stage grinding are sent to the flotation equipment for separation after slurry adjustment, and the flotation clean coal and tailing coal are obtained; d. Grading and dehydration operation: the tailing coal enters the tailing coal pond for buffering and then pumps it to the classifying cyclone for classification; e. Coarse slime tailing operation: the underflow of the classifying cyclone is fed to the spiral separator for tailing, and the heavy and light products of the spiral separation are obtained; The heavy product after the overflow of the grading cyclone and the spiral separation enters the concentrator and then concentrates and presses the filter; f. Curved sieve desliming operation: the light products after spiral separation enter the curved sieve for desliming and dehydration, and obtain the oversize and undersize; g. Grinding and dissociation operation: the oversieve is fed into the coal mill for grinding and dissociation. The mill speed can be adjusted according to the nature of the feed material and the dissociation particle size. The part with a dissociation particle size of 0.074mm accounts for 50-60%. The detached ore pulp is pumped to the slurry mixing equipment II for slurry mixing; h. Concentration and clarification of coal slime water: the overflow of the grading cyclone, the heavy product of the spiral separator and the sieve of the curved sieve are fed into the concentrator for concentration and clarification to obtain an underflow slurry with a suitable concentration for subsequent pressure filtration, and the overflow is used as Recycled water; I. Press filter operation: after buffering, the underflow slurry of the concentrator is pumped to the diaphragm quick-opening filter press for press filtration. The filter cake is used as the final tailing slime product, and the filtrate is used as circulating water. 2. A two-stage crushing and flotation process for coking medium coal according to claim 1, characterized in that: in step a, the crushing is below 1 mm.